newton's laws

newton’s first law

an object at rest tends to stay at rest and an object in motion stays in motion unless acted upon by an unbalanced force

• an object’s motion will only change when acted upon by an unbalanced force

inertia

an object’s tendency to resist any changes in its velocity

examples of interia

• when a bus suddenly stops, the passengers of the bus falls forwards

newton’s second law

the acceleration of a body is proportional to the acting force and inversely proportional to the mass of the body

• F↑, a↑

• m↑, a↓

$$\Sigma F = ma$$

• F = net force

• m = mass (kg)

• a = acceleration (m/s/s)

newton’s third law

• for every action there is an equal but opposite reaction

  • if an object exerts a force on object B, then object B will exert an equal but opposite force on object